I have an application with minimizable controls. Minimized items are displayed in a horizontal stackpanel. On resize (shrink) of the application items could be chopped because of too little space.
To avoid this my idea was to move chopped elements to an expandable control (like this)
The application follows the MVVM pattern, the items in the panel are in an ItemsControl bound to the view model.
My implementation for now is to use a custom panel where the chopped elements are handed out with a property "SpillOverElements". I wanted to bind another control (panel, expander or popup) to this property. The problem is that I am not able to bind to the "SpillOverElements" property of the "SpillOverPanel" inside the ItemsControl.
<ItemsControl>
ItemTemplate="{StaticResource DummyContentDataTemplate}"
ItemsSource="{Binding DisplayElementsCollection}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<local:SpillOverPanel />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
So the question is how could I bind to "SpillOverElements" property of the "SpillOverPanel". Any other ideas how to implement this are welcome, too. I am not sure if my way is the right approach.
Thanks in advance for your help!
Forgive me, there's a lot of spitballing in the text below.
A Single, Reusable ItemsControl class
This will probably be a rather involved implementation. You will likely need to create entirely new WPF Controls, in the form of both a "SpilloverItemsControl" class and a "SpilloverItem" class to serve as the item container, for items displayed in the spillover control. The SpilloverItemsControl class would of course inherit from ItemsControl.
The SpilloverItem container will expose a property - "IsSpilledOver" (or something like that), which the parent control will automatically set to true or false based on various size and visibility calculations.
Your SpilloverItemsControl class will be layed out as a sort of composite control, providing 2 different ItemsControls within its ControlTemplate - one whose items' Visibility will be set to Visible if "IsSpilledOver" set to 'false', and set to 'Collapsed' if not; and another one to serve as the 'spillover' area, which will display only the items with "IsSpilledOver" set to true.
An Alternate Approach
An alternative approach, but slightly less reusable, is to have the "IsSpilledOver" property exist in your item ViewModel, and create a minimal Behavior to determine when it should be set to true or false. Then in your View, you would again just have two different ItemsControls bound to the same collection. One to display the 'non spilled-over' items and one to display the 'spilled-over' items. The visibility here, would be set in your ItemTemplate.
Related
I have a sidebar in an application I am writing that displays information about the application's state to the user. In certain cases, the user can hover over various elements in the sidebar to view more specific details. These details are shown to the user using a control that mimics the behavior of Bootstrap's Popover control. I accomplish this using an invisible Canvas overlay that spans the entire window, and the "Popover" itself is placed relatively on this Canvas using computed Canvas.Left and Canvas.Top properties.
Here's a (very simplified) look at the current XAML of my application:
<Window>
<Grid x:Name="container">
<.. a lot of various nested elements ..>
<StackPanel x:Name="sidepanel">
.. content of the sidepanel control ..
</StackPanel>
</.. a lot of various nested elements ..>
<Canvas x:Name="overlay">
.. content of the Popover control ..
</Canvas>
</Grid>
</Window>
This works great, except that I'd like to refactor this functionality into a single control. However, I'm not sure how to proceed - if the custom UserControl includes the Canvas overlay in its XAML definition, I'll be unable to position the sidepanel portion of the control in the same way as it currently is positioned within the application. However, the Canvas overlay can't be nested inside of the sidepanel, as it needs to span the entire window in order to operate properly.
Is there a way to define a single UserControl that can sit in different parts of the logical tree? Or is there a better way to accomplish this effect?
You can't split a single UserControl into different places in the logical tree, but you can inject other code into a Control and place it around the internal components it defines. This is the model used by HeaderedContentControl: two content properties, Content and Header, which are injected into two different ContentPresenters in the control's template. Hence things like Expander and TabItem with externally defined content in multiple locations around intrinsic parts of the controls. In the case of a UserControl you would be placing them in the main XAML instead of a template so the bindings are a little different but the principle is the same.
Define two Dependency properties of type object on your UserControl and then bind those into ContentPresenters placed in the exact spots where you have "a lot of various nested elements" in your sample. Then when you use the UserControl you can just define whatever other elements you want under the UserControl element inside like <MyUserControl.MyContentProperty1> tags and they'll get placed inside your UserControl content.
Let me explain you my situation.
I have a base class called Shape, and several concrete classes like Triangle, Square, etc.
I have several data templates.
I'm building just one object. So I wouldn't use an ItemControl control, I would like to use a normal panel like the grid, and show the respective data template (in DataContext has the concrete item)..
The only way to do this is using an ItemsControl? Or there's another way.. because I'm just using one item and not a collection and display the correct template.
DataTemplates are used in much more than just ItemsControls
They are used to tell WPF how to draw any object in the Visual Tree. For example, if you stick a User class object in the VisualTree, a DataTemplate can be used to tell WPF how to draw that User object
They are most frequently used in controls with an ItemsSource or Content properties, because those are the most common way of inserting data objects into the VisualTree.
In your specific case where you only want to insert one data item into the VisualTree, I would suggest a ContentControl
<ContentControl Content="{Binding MyDataObject}" />
To tell WPF how to draw MyDataObject you can either use the ContentTemplate property and set it to a DataTemplate
<ContentControl Content="{Binding MyDataObject}"
ContentTemplate="{StaticResource MyDataTemplate}" />
or define an implicit DataTemplate that tells WPF to draw any object of a specific type using a specific template.
<DataTemplate DataType="{x:Type local:MyDataObject}">
<!-- Tell WPF how to draw MyDataObject here -->
</DataTemplate>
If you want to display a single item with a data template that is selected based on the item's type, you should use ContentControl or any of its derived classes.
I'm trying to figure out if there is a way to dynamically add controls into another control (I know this is a bit vague...). My program is in C# 4.0, and WPF. Basically, I'm trying to create a datagrid but as opposed to having normal type 'cells' (ie text, hyperlink etc), I need each cell to hold a number of items. I figured that this wasn't possible in the datagrid, so I'm trying to do the following: Using a stack panel, add a variable number of wrap panels. Each wrap panel will contain 7 grids, where each grid will hold the data I want (I'll likely use some user control in place of the grid I think...)
An example of the code I have so far...
<StackPanel Height="559" HorizontalAlignment="Left" Margin="24,11,0,0" Name="tyStackPanel" VerticalAlignment="Top" Width="783">
<WrapPanel Height="100">
<Grid Width="100" Height="100">
</Grid>
</WrapPanel>
<WrapPanel Height="100">
</WrapPanel>
</StackPanel>
Is there a way to create a variable number of Wrap Panels though? (ie like you would have a variable number of rows in a datagrid)
Any help and suggestions is much appreciated!
P.S. Figure I should explain what I'm trying to achieve a bit better. I have a collection of items, each with 5 properties that I want displayed together. These items are grouped by Name (like a row in a data column) and a column header (which is not one of the 5 properties). I want to group the collection by (Name, ColumnHeader) pairs, and then in each "cell" display those 5 properties. In the way I'm trying to set it up above, there would be a WrapPanel per 'Name' and a Cell/Grid contained in it for each ColumnHeader.
WPF supports this very well with the ItemsControl and its various derived controls, one of which is the DataGrid, which actually does support the scenario you're looking for.
Basically, when you use an ItemsControl, DataGrid or one of these item controls, you bind the ItemsSource to whatever property holds your data items, and define the DataTemplates for each item, which can be any arbitrarily-complex block of XAML. For DataGrid, you can swap a normal column for a DataGridTemplateColumn, which can, again, be as complex as you want.
Check out the Data Templating Overview for, well, an overview.
I am creating some custom user controls for WPF. This user controls contain custom dependency properties so I can fill them in the designer.
One of this properties is called "InnerUserControlType". This dependency proeprty is a custom enumeration containing some values like TextBox, ComboBox, Label, CheckBox, etc.
I would like to be able to set this property in my XAML pages in the designer and then see the user control change the displayed inner control depending on the property.
How should I implement this? The grid which will contain the inner control in my user control is a normal field, so it cannot be accessed from a static method property (like the dependency properties).
I want it to have it working in the designer so the designers can work easily.
Thanks a lot!
Put a ContentControl in the grid, bind the Content property to the UserControl via relative source
<ContentControl Content="{Binding RelativeSource={RelativeSource FindAnsector,
AncestorType={x:Tyle myNamespace:MyControl}}}"
and make a DataTemplateSelector that will check the value of InnerUserControlType and will return an appropriate data template containing the control that was asked for in the property.
Depending on your scenarios, you might need to make sure the controls in the data template have the right data context. If the data context of the controls should be the same as of the user control, then on the root element in the data template, add relative binding for data context. Something like (for the text box data template):
<TextBox DataContext="{Binding DataContext,
RelativeSource={RelativeSource FindAnsector,
AncestorType={x:Tyle myNamespace:MyControl}}}"
......
</TextBox>
EDIT:
I've noticed only the wpf tag and missed the silverlight one.
In Silverlight you don't have ...TemplateSelector properties, so use a converter instead.
I may be making this more complicated than necessary ... but here goes.
I have my MainPage.xaml, in there I have references to two other UserControl's, ResultsView, and DetailsView.
Inside of the ResultsView, I have a ListBox bound to an ObservableCollection of custom items, I have a DataTemplate that is rendering each item. The item has a CaseID, and when I click on it, it's displayed as a HyperlinkButton, I need a Command I've set in the MainPageViewModel to fire, which handles changing the visibility to hide the ResultsView, and show the DetailsView.
How do I bind the Command of the Hyperlinkbutton to the Command located in my MainPageViewModel?
Thanks in advance!
edit for clarification:
MainPage.xaml
<resultsView:ResultsView/>
<detailsView:DetailsView/>
Each of the two views (ResultsView & DetailsView) have their own ViewModel. So I'm going from my DataTemplate which resides in a ListBox inside my ResultsView, I need to go up to the MainPageViewModel, an extra step than your answer mentioned. Tried your method naming my MainPage.xaml to Name="mainPage", and using that as the ElementName in my HyperlinkButton, but no luck. I'll do some research on the RelativeSource option and see if I can make that work.
Thanks for your help so far.
edit 2: Forgot to add that the DataTemplate is in a ResourceDictionary, not in the ResultsView.
Well, it depends on the specific details, not all of which you've told us, but I can give you some examples.
Let's say that your DataTemplate for the custom items resides in the XAML of the ResultsView user control. That's a good spot for it but you might have put it in a resource dictionary.
As you say, the ListBox is bound to the collection of custom items. Let's further assume that the custom items collection is itself a property in your MainPageViewModel. And you've said clearly that the command you want to bind to is also in MainPageViewModel.
So the problem, which is a very common one, is that you are working inside a template associated with a binding to a collection, and so your DataContext is a custom item. It is no longer the main view-model itself. That's great as you show appropriate properties of the custom item like CaseID. But it's not great when you want to escape to the top-level of view-model.
If what I've said is true, then the ResultsView user control is in fact probably bound to the MainPageViewModel because you haven't "drilled into" the custom items collection yet. So, what you need to do is find a way using the binding syntax to reference the ResultsView user control from inside the DataTemplate for the ListBox. If you can do that, then you've escaped the collection.
There are two main approaches to do this:
ElementName syntax
RelativeSource syntax
I'll describe ElementName syntax and you can look up the other one.
Part 1) Name your ResultsView UserControl element like this:
<UserControl ....
Name="resultsView">
<!-- ... -->
Part 2) Inside your DataTemplate where you are defining the appearance of the hyperlink use the ElementName syntax to refer to that element:
<TextBlock>
<Hyperlink Command="{Binding DataContext.ItemDetailsCommand, ElementName=resultsView}"/>
</TextBlock>
So first we use ElementName to get the ResultsView UserControl element, and then we have a path with two pieces: the first piece is the DataContext property of the ResultsView which gives us the MainPageViewModel (yeah!), and then the property of the command we want to invoke.
That's one way to "escape" the binding and issue commands found at a higher level in the view-model.